Mechanic says not to use 4a all the time

[oldpaddy]

I'm on my third expy and I've always left them on 4a (4w drive auto). The mechanic says it's bad for the transfer case. What do you guys say?

I use 4a all the time because I live on a long dirt road and it rains a good bit here and we get snow/ice during the winter. I figure it's a good set and forget setting. I've never noticed it come on at highway speeds.

 

[JasonH]

I would think it's the opposite. Generally seals last longer with periodic lubrication. I think circulating the fluids in the transfer case on occasion would be a good thing. The AWD 4A is only going to activate when there's slippage anyway, so it's not like you're engaging the transfer case all the time.

 

[Trainmaster]

Follow your owners' manual. It's clear about these things. I doubt your "mechanic" has read much since high school, and has certainly not read about your transfer case.

 

[oldpaddy]

Follow your owners' manual. It's clear about these things. I doubt your "mechanic" has read much since high school, and has certainly not read about your transfer case.

The guy used to be a tech at a Ford dealership and he's the best mechanic in the shop. I know this because it's my father in-laws shop. Though I can't find anything saying he's right about this.

 

[jkayca]

I'm pretty sure it's mentioned in the manual not to do to leave in 4a or 4wd. Not sure of the mechanics of it.

Found this article which about 4wd drive systems Ford uses: https://www.blueovaltrucks.com/tech-articles/understanding-the-4wd-in-your-ford/

 

[Viper74656]

To quote from the manual, page 169: "This mode (4A) is appropriate for all driving conditions, such as dry road surfaces, wet pavement, snow, or gravel."

4H and 4L are a different story.

 

[Trainmaster]

I'd read the manual and forget what the wisest mechanic in town and people on a Web forum have to say.

Jkayca's link is also very helpful and the information is right from Ford:https://www.blueovaltrucks.com/tech-articles/understanding-the-4wd-in-your-ford/

 

[oldpaddy]

I'd read the manual and forget what the wisest mechanic in town and people on a Web forum have to say.

Jkayca's link is also very helpful and the information is right from Ford:https://www.blueovaltrucks.com/tech-articles/understanding-the-4wd-in-your-ford/

Yeah, I read that earlier and I couldn't find anything saying it's bad.

 

[99WhiteC5Coupe]

The guy used to be a tech at a Ford dealership and he's the best mechanic in the shop. I know this because it's my father in-laws shop. Though I can't find anything saying he's right about this.

Perhaps ask the mechanic WHY it is bad for the transfer case to drive in 4A all the time, and what problems can be caused by using 4A all the time?

 

[mr_dave]

4A definitely leaves the transfer case engaged, meaning more wear on that part and the front driveline, diff, axles, etc. Plus less mileage due to the extra drag. I believe it's just the hubs that auto-engage and disengage. I agree with the mechanic, it's probably not a good idea to leave it engaged 100% of the time since the transfer case wasn't designed for it. That being said, I try to exercise 4A and 4H whenever I can while on dirt roads to keep things lubed. While on dry pavement it's always in 2H.

Edit: My statement above isn't quite accurate, see this conclusion: https://www.expeditionforum.com/thr...-use-4a-all-the-time.48493/page-3#post-446021